Friday, January 3, 2025

Treatment of late-onset Pompe disease

Davalos L, Kushlaf H. Advances in Disease-Modifying Therapeutics for Chronic Neuromuscular Disorders. Semin Respir Crit Care Med. 2024 Dec 21. doi: 10.1055/a-2463-3385. Epub ahead of print. PMID: 39708835.

Abstract

Neuromuscular disorders can cause respiratory impairment by affecting the muscle fibers, neuromuscular junction, or innervation of respiratory muscles, leading to significant morbidity and mortality. Over the past few years, new disease-modifying therapies have been developed and made available for treating different neuromuscular disorders. Some of these therapies have remarkable effectiveness, resulting in the prevention and reduction of respiratory complications. For myasthenia gravis (MG), efgartigimod, ravulizumab, rozanolixizumab, and zilucoplan have been Food and Drug Administration (FDA)-approved for the treatment of acetylcholine receptor (AChR) antibody-positive generalized MG in the past 2 years. Rozanolixiumab is also approved for treating MG caused by muscle-specific tyrosine kinase (MuSK) antibodies. The new MG therapeutics target the complement system or block the neonatal fragment crystallizable (Fc) receptors (FcRn), leading to significant clinical improvement. For spinal muscular atrophy (SMA), nusinersen (intrathecal route) and risdiplam (oral route) modify the splicing of the SMN2 gene, increasing the production of normal survival motor neuron (SMN) protein. Onasemnogene abeparvovec is a gene replacement therapy that encodes a functional SMN protein. All SMA medications, particularly onasemnogene abeparvovec, have led to clinically meaningful improvement. For late-onset Pompe disease (LOPD), avalglucosidase alfa has shown a greater improvement in respiratory function, ambulation, and functional outcomes in comparison to alglucosidase alfa, and cipaglucosidase alfa combined with miglustat has shown improvement in respiratory and motor function in a cohort of enzyme replacement therapy-experienced LOPD patients. Amyotrophic lateral sclerosis (ALS) remains a challenge. The two most recent FDA-approved medications, namely sodium phenylbutyrate and tofersen, may slow down the disease by a few months in a selected population but do not stop the progression of the disease.

Dalmia S, Sharma R, Ramaswami U, Hughes D, Jahnke N, Cole D, Smith S, Remmington T. Enzyme replacement therapy for late-onset Pompe disease. Cochrane Database Syst Rev. 2023 Dec 12;12(12):CD012993. doi: 10.1002/14651858.CD012993.pub2. PMID: 38084761; PMCID: PMC10714667.

Abstract

Background: Pompe disease is caused by a deficiency of the enzyme acid alpha-glucosidase (GAA). People with infantile-onset disease have either a complete or a near-complete enzyme deficiency; people with late-onset Pompe disease (LOPD) retain some residual enzyme activity. GAA deficiency is treated with an intravenous infusion of recombinant human acid alglucosidase alfa, an enzyme replacement therapy (ERT). Alglucosidase alfa and avalglucosidase alfa are approved treatments, but cipaglucosidase alfa with miglustat is not yet approved.

Objectives: To assess the effects of enzyme replacement therapies in people with late-onset Pompe disease.

Search methods: We searched the Cochrane Inborn Errors of Metabolism Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched MEDLINE OvidSP, clinical trial registries, and the reference lists of relevant articles and reviews. Date of last search: 21 April 2022.

Selection criteria: We included randomised controlled trials (RCTs) of ERT in people with LOPD of any age.

Data collection and analysis: Two review authors independently assessed trial eligibility, extracted data, assessed the risk of bias and the certainty of the evidence (using GRADE). We resolved disagreements through discussion and by consulting a third author.

Main results: We included six trials (358 randomised participants) lasting from 12 to 78 weeks. A single trial reported on each comparison listed below. None of the included trials assessed two of our secondary outcomes: need for respiratory support and use of a walking aid or wheelchair. Certainty of evidence was most commonly downgraded for selective reporting bias. Alglucosidase alfa versus placebo (90 participants) After 78 weeks, alglucosidase alfa probably improves the six-minute walk test (6MWT) distance compared to placebo (mean difference (MD) 30.95 metres, 95% confidence interval (CI) 7.98 to 53.92; moderate-certainty evidence) and probably improves respiratory function, measured as the change in per cent (%) predicted forced vital capacity (FVC) (MD 3.55, 95% CI 1.46 to 5.64; moderate-certainty evidence). There may be little or no difference between the groups in occurrence of infusion reactions (risk ratio (RR) 1.21, 95% CI 0.57 to 2.61; low-certainty evidence), quality of life physical component score (MD -1.36 points, 95% CI -5.59 to 2.87; low-certainty evidence), or adverse events (RR 0.94, 95% CI 0.64 to 1.39; low-certainty evidence). Alglucosidase alfa plus clenbuterol versus alglucosidase alfa plus placebo (13 participants) The evidence is very uncertain about the effect of alglucosidase alfa plus clenbuterol compared to alglucosidase alfa plus placebo on: change in 6MWT distance after 52 weeks (MD 34.55 metres, 95% CI-10.11 to 79.21; very low-certainty evidence) and change in % predicted FVC (MD -13.51%, 95% CI -32.44 to 5.41; very low-certainty evidence). This study did not measure infusion reactions, quality of life, and adverse events. Alglucosidase alfa plus albuterol versus alglucosidase alfa plus placebo (13 participants) The evidence is very uncertain about the effect of alglucosidase alfa plus albuterol compared to alglucosidase alfa plus placebo on: change in 6MWT distance after 52 weeks (MD 30.00 metres, 95% CI 0.55 to 59.45; very low-certainty evidence), change in % predicted FVC (MD -4.30%, 95% CI -14.87 to 6.27; very low-certainty evidence), and risk of adverse events (RR 0.67, 95% CI 0.38 to 1.18; very low-certainty evidence). This study did not measure infusion reactions and quality of life. VAL-1221 versus alglucosidase alfa (12 participants) Insufficient information was available about this trial to generate effect estimates measured at one year or later. Compared to alglucosidase alfa, VAL-1221 may increase or reduce infusion-associated reactions at three months, but the evidence is very uncertain (RR 2.80, 95% CI 0.18 to 42.80). This study did not measure quality of life and adverse events. Cipaglucosidase alfa plus miglustat versus alglucosidase alfa plus placebo (125 participants) Compared to alglucosidase alfa plus placebo, cipaglucosidase alfa plus miglustat may make little or no difference to: 6MWT distance at 52 weeks (MD 13.60 metres, 95% CI -2.26 to 29.46); infusion reactions (RR 0.94, 95% CI 0.49 to 1.80); quality of life scores for physical function (MD 1.70, 95% CI -2.13 to 5.53) and fatigue (MD -0.30, 95% CI -2.76 to 2.16); and adverse effects potentially related to treatment (RR 0.83, 95% CI 0.49 to 1.40) (all low-certainty evidence). Cipaglucosidase alfa plus miglustat probably improves % predicted FVC compared to alglucosidase alfa plus placebo (MD 3.10%, 95% CI 1.04 to 5.16; moderate-certainty evidence); however, it may make little or no change in % predicted sniff nasal inspiratory pressure (MD -0.06%, 95% CI -8.91 to 7.71; low-certainty evidence). Avalglucosidase alfa versus alglucosidase alfa (100 participants) After 49 weeks, avalglucosidase alfa probably improves 6MWT compared to alglucosidase alfa (MD 30.02 metres, 95% CI 1.84 to 58.20; moderate-certainty evidence). Avalglucosidase alfa probably makes little or no difference to % predicted FVC compared to alglucosidase alfa (MD 2.43%, 95% CI -0.08 to 4.94; moderate-certainty evidence). Avalglucosidase alfa may make little or no difference to infusion reactions (RR 0.78, 95% CI 0.42 to 1.45), quality of life (MD 0.77, 95% CI -2.09 to 3.63), or treatment-related adverse events (RR 0.92, 95% CI 0.61 to 1.40), all low-certainty evidence.

Authors' conclusions: One trial compared the effect of ERT to placebo in LOPD, showing that alglucosidase alfa probably improves 6MWT and respiratory function (both moderate-certainty evidence). Avalglucosidase alfa probably improves 6MWT compared with alglucosidase alfa (moderate-certainty evidence). Cipaglucosidase plus miglustat probably improves FVC compared to alglucosidase alfa plus placebo (moderate-certainty evidence). Other trials studied the adjunct effect of clenbuterol and albuterol along with alglucosidase alfa, with little to no evidence of benefit. No significant rise in adverse events was noted with all ERTs. The impact of ERT on some outcomes remains unclear, and longer RCTs are needed to generate relevant information due to the progressive nature of LOPD. Alternative resources, such as post-marketing registries, could capture some of this information.

Kishnani PS, Byrne BJ, Claeys KG, Díaz-Manera J, Dimachkie MM, Kushlaf H, Mozaffar T, Roberts M, Schoser B, Hummel N, Kopiec A, Holdbrook F, Shohet S, Toscano A; PROPEL Study Group. Switching treatment to cipaglucosidase alfa plus miglustat positively affects patient-reported outcome measures in patients with late-onset Pompe disease. J Patient Rep Outcomes. 2024 Nov 13;8(1):132. doi: 10.1186/s41687-024-00805-w. PMID: 39535661; PMCID: PMC11561219.

Abstract

Background: Late-onset Pompe disease (LOPD), a rare autosomal recessive multisystemic disorder, substantially impacts patients' day-to-day activities, outcomes, and health-related quality of life (HRQoL). The PROPEL trial compared cipaglucosidase alfa plus miglustat (cipa+mig) with alglucosidase alfa plus placebo (alg+pbo) in adult patients with LOPD over 52 weeks and showed improved motor and respiratory function in patients switching treatment from standard-of-care enzyme replacement therapy (ERT) to cipa+mig at baseline. This study evaluated the impact of cipa+mig on patient-reported outcomes (PROs), including HRQoL in ERT-experienced patients, using data from PROPEL.

Methods: PROs evaluated included the Subject's Global Impression of Change (SGIC), Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Short Form 20a, PROMIS Fatigue Short Form 8a, Rasch-built Pompe-specific Activity (R-PAct), and European Quality of Life-5 Dimensions 5 Response Levels (EQ-5D-5L). The proportions of responders in the cipa+mig arm and the alg+pbo arm were compared via chi-squared or Fisher's exact test (patient-level responder analysis), and least squares (LS) mean differences were calculated for change from baseline at Week 52 of the PRO measures (group-level analysis).

Results: At Week 52, patient-level SGIC responder and group-level SGIC analyses favored cipa+mig compared with alg+pbo across all SGIC domains (e.g. 90 vs. 59% responders in the cipa+mig vs. the alg+pbo group for SGIC ability to move around; P = 0.0005; and LS mean difference 0.385; P = 0.02). Similarly, PROMIS Physical Function and Fatigue domains numerically favored cipa+mig in both analyses (e.g. 50 vs. 40% responders in the cipa+mig vs. alg+pbo arm for PROMIS Physical Function; P = 0.37; and LS mean difference 3.1; P = 0.11). R-PAct for both treatment groups was similar in the patient-level responder analysis, but numerically favored alg+pbo in the group-level analysis (35% responders in both arms; P = 0.95; and LS mean difference -0.8; P = 0.48). Self-care, usual activities, and depression/anxiety domains of EQ-5D-5L numerically favored cipa+mig in both analyses (e.g. 20 vs. 12% responders in the cipa+mig vs. alg+pbo arm for EQ-5D-5L self-care; P = 0.54; and LS mean difference -0.108; P = 0.52).

Conclusions: Overall, switching treatment from alglucosidase alfa to cipa+mig positively impacted PRO measurements during the double-blind period of PROPEL.

Mir M, Rouhani K, Rouhani K, Hassani M, Damirchi M, Yazdansetad S, Aghaei M. Significance of early diagnosis and treatment of adult late-onset Pompe disease on the effectiveness of enzyme replacement therapy in improving muscle strength and respiratory function: a case report. J Med Case Rep. 2024 Oct 8;18(1):486. doi: 10.1186/s13256-024-04837-0. PMID: 39375771; PMCID: PMC11459847.

Abstract

Background: Pompe disease, a rare autosomal recessive disorder, is caused by mutations in the acid α-glucosidase gene. Pompe disease is a congenital metabolic disorder that affects all organs, particularly the striated muscle and nerve cells. Diagnosis is typically confirmed through enzyme assays that reveal reduced acid α-glucosidase activity. Enzyme replacement therapy utilizing human α-glucosidase is an available treatment option. Timely diagnosis and treatment in the early stages of the disease significantly impact the effectiveness of enzyme replacement therapy in enhancing patient condition. Here, we present a case of a patient with Pompe disease diagnosed 20 years after the onset of clinical symptoms.

Case presentation: A 38-year-old Iranian Baloch woman referred to our rheumatology clinic with progressive muscle weakness presents with a complex medical history. On mechanical ventilation for 12 years, she has endured fatigue and limb weakness since the age of 16, exacerbated following an abortion at 19. Despite undergoing corticosteroid and azathioprine therapies, the suspected diagnosis of inflammatory myopathy did not yield improvement. Hospitalization at 23 due to respiratory failure post-pregnancy led to her continued reliance on a ventilator. A dried blood spot test indicated reduced GAA enzyme activity, confirming a diagnosis of Pompe disease through genetic testing. Treatment with myozyme for 2 years demonstrated limited efficacy, as the patient experienced improved breathing but no significant overall improvement in limb-girdle muscular weakness. This case underscores the challenges and complexities involved in diagnosing and managing rare neuromuscular disorders like Pompe disease.

Conclusion: Early intervention with enzyme replacement therapy plays a crucial role in halting further muscle loss and disease progression in Pompe disease patients. It is important to note that treatment during advanced stages of the disease may not yield substantial benefits. Nevertheless, enzyme instability and denaturation due to temperature and neutral pH levels, along with limited delivery to disease-relevant tissues, can pose challenges in treatment. However, timely diagnosis of Pompe disease is paramount for its effective management and improved outcomes.

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